1. Transfer 50 ml of embryo cultures
to centrifuge tubes. Spin at 1500 rpm for 5 minutes. Check
that you can see a pellet of embryos at the bottom.Quickly pour off the ASW. Try to remove as much as
possible, but don't worry about a little ASW left in the
tube.

2. Gently swirl tube to resuspend
the embryos. Add 40 ml of ice cold methanol and allow to fix
on ice for no more than 20 min. By this time, the embryos
should have settled to the bottom of the tube.

3. Decant off the methanol and
resuspend the embryos about 25 ml ice cold ASW.

4. ON ICE, let the embryos settle to
the bottom of the tube by gravity.

5. Decant off the ASW and resuspend
the embryos in fresh ice cold ASW. (At this point embyros
can be stored in refrigerator)